The invention relates generally to switching devices, such as for machine guarding in industrial applications, and particularly to reteachable switching circuits with an ability for locking.
Certain switching devices are known and are in use for controlling devices in technical installations in a manner to prevent human access to machines, such as presses and so forth. Typically, such switching devices are configured to facilitate partial or complete shutdown of electrically driven machines/devices of the technical installation to avoid or reduce the opportunities of access to equipment when operational.
One typical application of such a switching device is a door switch that includes an actuator-sensor combination for detecting an open state of an access door of the technical installation (e.g., a press). Typically, the actuator is coded with a unique identification code that is utilized by the sensor to detect the open state of the access door. In general, it is desirable to provide switching devices that can be retaught new actuators. However, certain users of such devices require the switching devices to be locked against reteaching of new actuators.
Certain manufacturers provide separate switching devices having different catalogue numbers for re-programmable and non re-programmable switches. However, this results in double inventory of the switching devices which may be expensive to maintain.
Accordingly, it would be desirable to provide a switching device that can be retaught new actuators, while providing the flexibility of locking the device against reteaching of new targets.